DSM-5: Handle With Care
A Short Review By Dr Joel Paris
May, 2013 marks the publication of DSM-5, the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM), published by the American Psychiatric Association (APA), the first major revision in more than 30 years. The DSM system has had a profound influence on all the mental health professions, and revisions of the manual are front-page news.
This book is a guide to the main features of the new manual, and their implications for practice. It will also focus on the ideology behind DSM-5. It is assumed that psychopathology lies on a continuum with normality, leading to a danger of overdiagnosis. The assumption that mental disorders are brain disorders may be correct, but the evidence is not there to prove it. Since we do not yet know enough to develop a classification based on data, it may better to keep a known system, however faulty, than make modifications with unpredictable consequences. Also, some revisions lack clinical utility, and each edition of DSM has grown larger, more complicated, and thicker.
Over the last 33 years, constant use of DSM manuals has given clinicians the impression that the categories they describe must be valid. That is not true. DSM-5 lacks the data to define mental disorders in the way that physicians conceptualize medical illnesses. Psychiatry is far behind other specialties in grounding categories in measurements independent of clinical observation. Almost all DSM diagnoses are based entirely on signs and symptoms. For this reason, any claim that DSM-5 is more scientific than its predecessors is little but hype. Radical changes in classification will require much more knowledge about the causes of mental disorders. Psychiatry has bet on neuroscience as the best way to understand mental disorders, to solve problems in diagnosis, and to plan treatment. Only time will tell how this wager will pan out. Although progress in brain research has been rapid and impressive, its application to psychiatry has thus far been very limited. Neuroscience has shed great light on how the brain functions, but we do not understand the etiology or the pathogenesis of the most severe mental disorders.
DSM-5 is not “the bible of psychiatry” but a practical manual for everyday work. Psychiatric diagnosis is primarily a way of communicating. That function is essential but pragmatic—categories of illness can be useful without necessarily being “true.” The DSM system is a rough-and-ready classification that brings some degree of order to chaos. It describes categories of disorder that are poorly understood and that will be replaced with time. Moreover, current diagnoses are syndromes that mask the presence of true diseases. In the absence of a more fundamental understanding of disease processes, DSM-5, like its predecessors, had no choice but to continue basing diagnostic criteria on signs and symptoms. But observation needs to be augmented by biological markers, as has been done in other medical specialties. In the absence of such markers, we cannot be sure that any category in the manual is valid. We should therefore not think of current psychiatric diagnoses as “real” in the same way as medical diseases.
Every edition of DSM has expanded the frontier with normality, taking on more and more problems of living as diagnosable disorders. Psychiatric classification has become seriously over-inclusive, and the manual grows ever larger. DSM-5 errs on the side of expanding its boundaries—mainly out of fear of “missing something” or not including problems that psychiatrists treat in practice. The result is that people with normal variations in emotion, behavior, and thought can receive a psychiatric diagnosis, leading to stigma and inappropriate treatment.
Because we have to live with a diagnostic system that is provisional—and that will almost certainly prove invalid in the long run—much of the research on mental disorders has to be taken with a grain of salt. For example, although a massive amount of data has been collected on the epidemiology of mental illness, almost all results depend on the current diagnostic system. Similarly, studies of treatment methods in psychiatry that target specific disorders are sorely limited by the problematic validity of categories. Most treatments, ranging from antidepressants to cognitive behavioral therapy, have broad effects that are not specific to any diagnosis.
The editors of DSM-5 see disorders as dimensions—spectra of pathology that can be scored in terms of severity. But measuring the severity of depression is not like taking blood pressure. The definition of dimensions is based on observation rather than biological markers. Dimensional diagnosis also runs the risk of being over-inclusive. Normal people have symptoms that do not deserve a formal diagnosis.
DSM-5 is not a scientific document but a product of consensus by committees of experts. It is a revision that can be considered as a draft for future editions that will be based on more data. Psychiatry has to put off scientifically based definitions of mental disorders to a future time when it knows more.
DSM-5 is a poor guide to therapy. The system was never intended to guide treatment. As mental health practice becomes increasingly evidence-based, it could eventually develop specific treatments for diagnoses based on research. Doing so is not possible now. Only a few well-established links are known between any diagnostic category and specific therapeutic options.
Although some radical changes were proposed for DSM-5, the final product involves only a few serious revisions. The multi-axial system introduced in DSM-III has been eliminated. The criteria for some categories, particularly generalized anxiety disorder and attention-deficit hyperactivity disorder, have been expanded. The grief exclusion for diagnosis of major depression has been eliminated, but clinicians are warned not to diagnose depression too readily in such cases. Substance use disorders now use the term addiction, and no longer distinguish between dependence and abuse. Overly aggressive children can now be diagnosed as having disruptive mood regulation disorder. Autism spectrum disorders now include both classical autism and Asperger’s syndrome. Dementias are now classified as neurocognitive disorders, rated by severity. Somatic symptom disorders replace somatoform disorders and are classified differently.
None of these changes is likely to affect clinical practice in a major way. Psychiatry can only hope that further progress in research will make DSM-6 a more scientific document.
Dr. Joel Paris
Research Associate, Jewish General Hospital
Professor, Department of Psychiatry, McGill University
Editor-in-Chief, Canadian Journal of Psychiatry
Joel Paris was born in New York City, but has spent most of his life in Canada. He obtained an MD from McGill University in 1964, where he also trained in psychiatry. Dr. Paris has been a member of McGill’s Psychiatry Department since 1972. Since 1994, he has been a full Professor, and he served as Department Chair from 1997 to 2007. Dr. Paris is currently a Research Associate at the Jewish General Hospital. He is also Editor-in-Chief of the Canadian Journal of Psychiatry.
The Intelligent Clinician’s Guide to the DSM-5® explores all revisions to the latest version of the Diagnostic and Statistics Manual, and shows clinicians how they can best apply the strong points and shortcomings of psychiatry’s most contentious resource. Written by a celebrated professor of psychiatry, this reader-friendly book uses evidence-based critiques and new research to point out where DSM-5 is right, where it is wrong, and where the jury’s still out. Along the way, The Intelligent Clinician’s Guide to the DSM-5® sifts through the many public controversies and clinical debates surrounding the drafting of the manual and shows how they inform a modern understanding of psychiatric illness, diagnosis and treatment. This book is necessary reading for all mental health professionals as they grapple with the first major revision of the DSM to appear in over 30 years.